function RDSClient(options) {

  if (!(this instanceof RDSClient)) {

    return new RDSClient(options);

  }

  Operator.call(this);

  let configObj = JSON.stringify(options);

  let len = configObj.match(/\{/g);

  if (len.length > 1) {

    delete options.connectionLimit;

    delete options.database;

    let poolCluster = mysql.createPoolCluster({

      removeNodeErrorCount: 1,

      defaultSelector: "RR" //RR,RANDOM,ORDER

    });

    for (let node in options) {

      poolCluster.add(`${node}`, options[`${node}`]);

    }

    this.pool = poolCluster.of('*', 'RR');

    console.log('<<<<<<----mysql createPoolCluster---->>>>>>>', options, len)

  } else {

    this.pool = mysql.createPool(options);

    console.log('<<<<<<-----mysql createPool--->>>>>>>', options, len)

  }

  [

    'query',

    'getConnection',

  ].forEach(method => {

    this.pool[method] = promisify(this.pool[method]);

  });

}

'use strict';

const assert = require('assert');

const rds = require('ali-rds');

let count = 0;

module.exports = app => {

  app.addSingleton('mysql', createOneClient);

};

function createOneClient(config, app) {

  const client = rds(config);

  app.beforeStart(function* () {

    const rows = yield client.query('select now() as currentTime;');

    const index = count++;

    app.coreLogger.info(`[egg-mysql] instance[${index}] status OK, rds currentTime: ${rows[0].currentTime}`);

  });

  return client;

}